Based on the smartphone in his hand on page 29, I'm assuming he's a transmigrator rather than a reincarnator and some fucked up deity (probably the human god of this world) brought him over and said "go nuts".
I think he has, but he's still not really in a position to do anything about it. After all, while he did avert several crises that significantly impacted the plot and would eventually lead to game!Harold's downfall, he was also implicated as a traitor in the process due to his tactics.
And the...
The problem there, though, is that simpler stories don't really draw in and retain readers to the same degree. And since readership is (figuratively) life or death for a series, you get cliffhangers and multiple plot threads and the like. Anything to keep readers coming back chapter to chapter.
I wouldn't bother, mate. Dipshits like that feel personally attacked if the MC isn't fucking everything with a hole every chance they get, regardless if it'd be rape (for either party) or general appropriateness of the TPO.
I like that they're already asking the question of why the heroes were discarded when their skills were clearly powerful before MC gets too OP from combining them.
And the answer, based on implication, is just that the ones doing the summoning are shallow fucks who judge by appearance (re: how...
That's the problem of having a protagonist with hypnosis powers in a mainstream series. If he were enough of a scumbag to take advantage, this would be a straight up hentai series and, well, hentai with hypnosis are (almost) literally a dime a dozen.
But if he were less of a scumbag, he...
It's also waaay easier to ensure it actually gets on him, since the demon has to be close to attack, whereas throwing mud (assuming the demon would even allow them the time to make some) can miss.
(Sorry for dragging this back up; I forgot all about this series from lack of updates and am rereading it now.)
The best part is that he, strictly speaking, didn't have to. He was fully within his right as the victor of the duel to just go about his business and quietly become a better person...
At least this one actually had people nearby to try and help him; as opposed to being a cooling corpse for everyone to discover when they clock in for the day.